Burglar alarm



Feb. 3. 1925.

G. MARSHALL BURGLAR ALARM Filed Oct. 21, 1924 INVENTOR':

Patented Feb. 3, 1925.

BU-RG LAR ALARM;

Application. filed October 21, 1924. Serial N'o.v 744,871.

To all whom it may concern:

Be it known that I, Gnonon MARSHA L,

a citizen of the United States, residing at Philadelphia, in the countyof Philadelphia and State of Pennsylvania, have invented a certain newand useful Burglar Alarm,

of which the following is a specification:

This invention, generally stated, relates to signals. or alarms. and hasmore especial relation to a device for a-udibly announcing A furtherobject resides in the providing.

of general arrangement, construction and connection of parts forattaining-the results sought by the leading object. 7,

Other and further objects not at this time ap caring will. behereinafter more specifical y referred to.

The invention consists of the novel construction hereinafter describedand finally laimed.

The nature, characteristic features and scope of the invention will bemore fully understood from the following description aken in connectionwith the accompanying drawings forming part hereof, and inwhich:

Fig. 1, is a fragmentary view, partly sectioned, of a window frame andcomplemental sash showing my burglar alarm operatively arranged withrespect to the lower sash.

Fig. 2, is a view in elevation of the burglar alarm detached.

Fig. 3, is anend view of Fig. 2, and

Fig. 4, is a top or plan view of Fig. 2.

For the purpose of illustrating my invention I have shown in theaccompanying drawings one form thereof which is at present preferred byme, since the same has been found in practice to give satisfactory andreliable results, although it is to be understood that the variousinstrumentalities of which my invention consists can be mentalities asherein! shown and described;

Referring to the drawings in detail the reference numeral 1' designatesa plate of rectangular configuration. This plate 1 is provided withopenings 2 for screw accommodation whereby the plate may be secured tothe frame 3 of a window as clearly shown in Fig. 1. y The. plate 1 has.preferably formed integral therewith at its top a lateral extension aterminating at its; top ina hearing 5, which bearing including said;lateral: extension. has averticalv openinggor passage 6 extendedentirely therethrough for a purpose to presently appear. Preferablyformed integral with the lower part of'plate- 1 andextended laterallytherefrom is an. extension 7 having a. screw threaded: opening arrangedvertically theret-hrough to. receive the screw threaded end: of aspring" barrel 8 containing a coiled. spring: 9,. Also carried by aplate 1, arranged intermediate the extensions 4.- and- 7 and providedwith aniape'rture in alignment with the opening through extensiond: andthe opening in; springbarrel 8 is a lateral extension: 10 forming a.bearing for avertically disposed: plunger 11.. The: plunger 11: isshowlrasbeing cylindrical in form, has its lower end engaging in a loose fitwith the interior of spring barrel 8, and is provided at its upper endwith a nib 12. This nib in the operation of the burglar alarm is adaptedto strike the head of a percussion cap and cartridge 13 positioned inthe opening through extension 4. and bearing 5. The plunger 11 isprovided with a slotted portion 14. Having pivotal relation as at 15with an extension 16 of plate 1 is a trip lever 17. This trip lever 17is provided at its inner end with a bevelled portion 18 adapted toengage the slotted portion let of plunger 11, as clearly shown in Fig.2.

A description will now be given of the mode of operation of the abovedescribed device: To set the burglar alarm the lower sash 19 of a windowin closed position is adapted to have rested upon the top thereof theend 20 of the pivotal lever 17. The bevelled end 18 of which lever ispositioned within the slot 14 of plunger 11. In this position of partsno tension is being exerted upon spring 9. Upon an unauthorized personraising the window sash 19 the pivotal lever 17 is moved from theposition shown in full lines to that shown in dotted lines, during whichmovement plunger 11 has been depressed to compress spring 9. As thewindow sash 19 is continued to be raised the bevelled end 18 of lever 17disengages from the slot of plunger 11 whereupon spring 9 forces plunger11 forward- 1y so that the nib 12 is impelled against the percussion capof cartridge 13 and exploding same to notifv the occupants of thebuilding that unauthorized entry is being attempted. The bevelled end 18of lever 17 is maintained in a normal horizontal position by means ofstop 20 carried by plate 1.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In a device of the character stated, a plate provided at its lowerportion with a barrel containing a coiled spring, a slotted plungercapable of vertical movement with respect to said plate, the lower endof which plunger is loosely fitted within said barrel upon said spring,a lever pivoted to said plate, one end of said lever being adapted toengage within said plunger slot, which lever when tripped being adaptedto cause compression of said spring, means carried by said plate forlimiting the movementof said lever and plunger and a percussion capcarried by the upper part of said plate in register with said plunger.

2. In a device of the character stated, a plate adapted for attachmentto a window frame provided at its lower portion with a barrel containinga coiled spring, a slotted plunger capable of vertical movement withrespect to said plate, the lower end of Which plunger is loosely fittedwithin said barrel upon said spring, means carried by the plate to guidesaid plunger, a lever pivoted to said plate, one end of said lever beingadapted to engage within said plunger slot, which lever when trippedbeing adapted to cause compression of said sprin the end of said leverengaging said slot being bevelled so as to disengage from said slotduring downward movement of said bevelled end, means carried by saidplate for limiting the movement of said lever and plunger and apercussion cap carried by the upper part of said plate in register withsaid plunger.

3. In combination a window frame, a window sash, a plate secured to thewindow frame, a barrel containing a coiled spring carried by the lowerend of said plate, a slotted plunger paralleling said plate and havingits lower end loosely fitted Within said barrel upon said spring, alever pivoted to said plate, one end of said lever engaging said slotand the other end of said lever lying in the path of travel of saidwindow sash, whereby upon raising of said sash said lever is moved aboutits pivoted point to cause compression of said spring, means carried bysaid plate for limiting the movement of said lever and plunger and apercussion cap arranged in alignment with said plunger and carried bythe top of said plate.

In testimony whereof, I have hereunto signed my name.

GEORGE MARSHALL.

